#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int how[101] = {};
	string a;
	int n,ma = 0;
	cin >> n;

	for(int i = 0;i < n;i++){
		for(int j = 0;j < n;j++){
			cin >> a;
			if(a == "nyanpass") {
				how[j]++;
			}
		}
	}
	int ans = INF;
	for(int i = 0;i < n;i++){
		if(how[i] == n-1) {
			if(ans != INF) {
				ans = INF;
				break;
			}
			ans = i;
		}
	}
	if(ans == INF) cout << "-1" << endl;
	else cout << ans + 1 << endl;
	return 0;
}